An ecologist is travelling yet again to one of the world's most important seabird breeding grounds in Western Australia to try to uncover what impact the changing environment is having on the colonies.

Located about 80 kilometres off the coastal city of Geraldton, the Abrolhos Islands are home to millions of seabirds which travel from the northern and southern hemispheres to breed and nest on the uniquely tropical system of reefs.

For 23 years, Dr Chris Surman has been travelling to the islands to collect data on the seabirds.

He says the Abrolhos is home to the globe's largest populations of some types of birds.

Dr Surman says the islands are attractive to an array of bird species because they act as a confluence between tropical warm waters and cooler southern waters.

"We have some Antarctica species there that are nesting at their most northern limits and we have tropical species breeding at their most southern point," he said.

"So it's internationally and nationally significant - it's pretty much off the radar as far as that goes at the moment."

Despite the significance of the site, the breeding success of many seabirds on the Abrolhos has been declining over recent decades.

Dr Surman, his partner Lisa and son Shae, are spending the Christmas holiday period at a number of islands within the network's Pelsaert Group to research whether that decline is being driven by changes in the Leeuwin current.

The current carries the birds' major food source in the form of tiny larval crustaceans.

When the Leeuwin current, which flows down the WA coast, is weaker, food supplies for the birds are greatly reduced and the birds tend to breed later in the season with less success.

Normal breeding period after a decade of disruption

During a trip to the Abrolhos earlier in the year, Dr Surman says it appeared that for the first time in about a decade, seabirds are breeding at a more 'normal' period.

He says they are laying their eggs in August and September this year, rather than the recent decade trend in the November and December months.

"Which suggests that this year there seems to be a super-abundance of food supply, for the birds to get into breeding that early after a fairly late season last year," he said.

Seabird expert and Conservation Council of WA volunteer, Nic Dunlop, has been studying the establishment of new and frontier colonies of tropical seabirds south of the Abrolhos for about 30 years.

Dr Dunlop says Dr Surman's long-term data sets on the seabirds suggest that the acceleration in the establishment of those fresh colonies appears to be closely linked to birds searching for food.

"Because what forces seabirds to normally naturally go back to their own breeding areas, the areas in which they hatched to become breeders, that situation only tends to break down when the area that they come from no longer supports the same number of birds," he said.

"So it forces the young, when they get to a breeding age, to disperse."

Dr Dunlop says shifts in marine ocean climate are reducing the productivity off the central west coast of WA, which impacts the seabirds.

"So there are climate change winners and losers in the suite of species we're looking at," he said.

He says seabirds are an indicator of the overall health of ecosystems like the sensitive Abrolhos Islands.

"Because they're on top of the food chain they're basically giving us a level of information about what's happening below them," he said.

"In terms of what's happening to the plankton, what's happening to the zooplankton, what's happening to the small fishes; all the things that eventually end up with birds being part of that system."

Island visitors aware of significance of seabird colonies

Pia Boschetti is a pearl farmer at the Abrolhos Islands who spends about five months of the year living at the islands.

She says Dr Surman's knowledge of the local seabirds has made many island users more aware of the significance of the site.

"There's birds that we see ...that we think are in huge amounts, but it's a rare breeding ground, one of only two in the world."

Pia Boschetti

"Normally I only care about things that are under the water, but the birdlife, obviously above the water, he's helped to show me that that's exciting." she said.

"It just blows me away because I've been going to the islands since I was born and I've never really paid much attention to the birds, other than the seagulls around and a few pretty birds.

"So I think about how he's educated me and how great it is when I get to tell a story to someone on how important it is.

"There's birds that we see over there that we think are in huge amounts, but it's a rare breeding ground, one of only two in the world - which is something I've found out from Chris."

She says Dr Surman's knowledge has helped improve the community's understanding and appreciation of the seabirds.

"He's made me really aware of the impact that we can have on the islands," she said.

"I don't think anyone would have known how important the birds are until Chris and Lisa did their research."

"I really think the research that they've done, no one would have done anything like that before and it's going to help decide what things to do at the islands as well."

"That data can assist with commercial applications as well as tourists applications and just general wellbeing for the place."

Colonies indicator of overall marine health

Dr Surman says the relationship between how seabirds perform at the Abrolhos is a proxy for the health of WA's overall marine environment.